Forum/Profile Avatar…

Kinda off topic I know, but how do I get me one of them fancy Avatars next to my posts on the Forum??? I took a look at the profile edit page but don’t see any way of adding an image… Am I missing something obvious or is this an “Off Site” Gravatar thing?

Keeping on this post, how do I get my posts authors to show up as a monster or random image? Cause when I look at them now they show up as a question mark.?. when users don’t upload a pic. I set my setting to monsters in my admin, does that mean every user thereafter will receive a monster pic?